Technical Field
This application relates generally to secure network-based communications using cryptographic protocols such as SSL.
Brief Description of the Related Art
Distributed computer systems are well-known in the prior art. One such distributed computer system is a “content delivery network” or “CDN” that is operated and managed by a service provider. The service provider typically provides the content delivery service on behalf of third parties (customers) who use the service provider's infrastructure. A distributed system of this type typically refers to a collection of autonomous computers linked by a network or networks, together with the software, systems, protocols and techniques designed to facilitate various services, such as content delivery, web application acceleration, or other support of outsourced origin site infrastructure. A CDN service provider typically provides service delivery through digital properties (such as a website), which are provisioned in a customer portal and then deployed to the network. A digital property typically is bound to one or more edge configurations that allow the service provider to account for traffic and bill its customer.
Secure Sockets Layer (SSL) is a well-known cryptographic protocol that is used to secure communications over networks such as the Internet. Cryptographic protocols such as SSL are often based on public key cryptographic systems, such as the RSA (Rivest, Shamir and Adelman) encryption algorithm. For a traditional RSA-based SSL session, the two sides of a connection agree upon a “pre-master secret” (PMS) which is used to generate the parameters for the remainder of the session. Typically, the two sides use RSA asymmetric encryption to establish the pre-master secret without exchanging the actual value in plaintext. In operation, the SSL client generates the pre-master secret and encrypts it with the SSL server's publicly available RSA key. This generates an encrypted pre-master secret (ePMS), which is then provided to the SSL server. The SSL server has a private decryption key, which is then used to decrypt the encrypted pre-master secret. At this point, both the client and the server have the original pre-master secret and can use it to generate the symmetric key used for actual encrypted and secure data exchange.
Decrypting the encrypted pre-master secret is the only time in the SSL connection that the private key is needed. This decryption occurs at a so-called SSL termination point. In many instances, the SSL termination point is insecure, and thus the storage and use of that key there presents significant security risks.